EP3532185B1 - Multilayer filter or sterile packing, manufacturing process and use of the filter - Google Patents

Description

Field of invention

The present invention relates to a multi-layer filter for a medical sterilization container or a sterile packaging consisting of or equipped with the multi-layer filter, a method for producing the same and the use of the multi-layer filter in a medical sterilization container or in a medical sterile packaging. The multi-layer filter or the sterile packaging formed therefrom or comprising it has a core layer made of an aramid fabric which is completely (on both sides) covered by at least one outer layer made of another material, preferably a filter material, e.g. PTFE is enclosed according to the sandwich principle (at least three layers).

Background of the technology

Sterilization filters (also sterile filters or filter units) are mainly used in medical sterilization containers (also sterile containers or sterile containers) for storing surgical utensils, surgical material or other sterile items. Sterilization filters for sterile filtration for medical sterilization containers are usually designed in the form of a flat, for example circular, filter disk. The filter disk has fluid exchange openings (also called pores) which enable the exchange of fluids, in particular gases, between the environment and the interior of the medical sterilization container. The (medical) sterilization filter is held, for example, in a filter holder that is attached / formed on the medical sterilization container. The filter holder clamps the sterilization filter between a first and a second holding surface or a first and a second holding frame.

Medical sterilization containers are generally used to sterilize, transport and store surgical instruments or materials (e.g. also artificial implants). An opening in the container wall is required so that hot steam can get into the medical sterilization container during the sterilization process, preferably in an autoclave. However, so that no germs, bacteria or the like can get into the container via the opening after sterilization, it is closed / covered with the above-mentioned sterilization filter before the sterilization process. The sterilization filter allows fluid to be exchanged, but does not allow any penetration into the medical sterilization container. In other words, the opening of the medical sterilization container is closed by a filter unit which has many small fluid exchange openings / pores that allow an exchange of fluids or its molecules, but prevent the penetration of germs, bacteria or the like after the sterilization process.

State of the art

The materials used for sterile filters of sterilization containers or for sterile packaging of sterile goods consist of cellulose, polypropylene (e.g. Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon®, DuPont) according to the generally known state of the art ). As a rule, the materials are used as interwoven fibers, stretched films, or in sintered form in sterile filters or sterile packaging. Polytetrafluoroethylene (abbreviation PTFE, occasionally also polytetrafluoroethene) is an unbranched, linearly structured, partially crystalline polymer made from fluorine and carbon. Colloquially, this plastic is often referred to by the trade name Teflon from DuPont. Other frequently used trade names from other manufacturers of PTFE are Dyneon PTFE (formerly Hostaflon) and Gore-Tex for PTFE membranes. DE 694 34 602 T2 discloses a sterile medical drape package comprising an outer drape made from a first sterilization layer and lying on an inner drape made from a second sterilization layer, each layer being independent of one another. The sterilization layers can be connected to one another at their outer edge.

Since sterile filters are used in sterilization containers for the sterilization of surgical instruments or material or as packaging for sterile goods, it can happen that the sterile filter comes into unintentional contact with surgical instruments and thus a defect can arise in the filter. Surgical Cutlery, such as knives, scalpels, clamps, staples, needles, saws, cannulas, nails, screwdrivers, sharp spoons, tweezers, scissors, chisels or drills, can have cutting edges and / or points that mechanically penetrate the filter and this can damage. Damage or a defect is present when an opening is made in the sterile filter through the filter material which is larger than a fluid exchange opening. A damaged filter cannot guarantee sterility in the sterilization container after the sterilization process. In other words, the disadvantage of the already known materials is that they offer / provide only little mechanical protection / resistance (eg puncture resistance) compared to the objects packed therein or the cutlery stored in the sterilization container. And if the filter is damaged, contaminants can get into the sterile container.

Summary of the invention

In view of this situation, the object of the present invention is to provide a filter or a sterile packaging which is difficult to damage in the event of unintentional mechanical contact with the sterile goods, for example surgical instruments or the like. A puncture-proof filter or a puncture-proof sterile packaging should preferably ensure a safe, sterile exchange of media in a medical sterilization container or in a sterile goods packaging, as well as the safe storage of the sterile goods packaged therein. The filter / packaging material should preferably be in the form of a flexible film material. Furthermore, the contents should be protected from contamination that can arise from damage to the filter or the like.

This object is achieved by a multi-layer, preferably sandwich-like filter for a medical sterilization container (s) or a sterile packaging of sterile goods with the features of the independent claims. Advantageous embodiments of the invention are the subject of the subclaims.

The basic idea of the invention consists in forming the core layer, preferably the middle layer, of the (sandwich-like) filter / sterile packaging (material) from an aramid fabric. The core layer is surrounded or preferably completely (also at the edge), preferably PTFE, surrounded by at least one outer layer made of at least one other (filter) material in accordance with a sandwich structure (at least three layers). As a result of the complete inclusion of the aramid fabric, no aramid fabric fibers, which may become detached, can get into the sterile container.

All layers of the filter, i.e. both the preferably at least two outer layers made of a (filter) material and the core layer made of aramid fabric, form / have fluid exchange openings (pores) that facilitate the exchange of fluids, in particular gases, between the environment and enable the inside of the sterile container / sterile packaging and create puncture protection. To put it more concretely, the preferably two outer layers take on the actual filter function, whereas the aramid fabric (arranged in between) (exclusively) takes on the puncture protection function, whereby its pores can be (significantly) larger than the pores of the preferably two outer layers. It should be pointed out here that the filter function of the two outer layers can preferably be achieved as a result of their respective pore size and / or their respective 3-dimensional (sponge) structure. In other words, especially in the latter case, the pores of the outer layers can even be larger than the smallest germ and yet even the smallest germs cannot pass through the layers.

This means that only fluids such as air or water vapor can pass through the preferably three-layer membrane thus formed; larger particles such as bacteria and spores are retained at least by the outer layers of filter material. If, in the case of a sandwich construction, a mechanical effect (piercing / cutting) takes place on one of the two outer layers, this may be injured / damaged in such a way that it loses its filter function. In the meantime, the filter function of the other outer layer is retained, since the aramid fabric separating the two outer layers pierces / cuts through the whole Prevents filter / packaging membrane up to the other outer layer and thus at least maintains / protects its filter function.

The fluid exchange openings / pores can have essentially the same size or the same diameter in all layers of the multilayer filter / sterile packaging, or the fluid exchange openings / pores of the central piercing protective layer / protective layer (aramid fabric) can be larger than those of the outer filter / Packaging layers or layers.

In one embodiment, the individual plies / layers can be designed as filter disks. In other words, the cross section of the filter can consist of at least three layers or at least three individual filter disks, for example. The at least one first, outer (lower) layer or filter disk can be one of the known filter materials from the cellulose or plastic or polymer group, preferably polypropylene (eg Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon ®, DuPont), which are present as interwoven fibers, stretched film, or in sintered form. The second layer or filter disc (the middle layer / the core layer) consists of the aforementioned aramid fabric. The at least one second, outer (topmost) layer or filter disk lying thereon also consists again of one of the filter materials of the above-mentioned group of the first layer. In this preferred case, the aramid fabric is, so to speak, embedded in the other two materials or, in other words, it is encased by them (like a sandwich). The two outer layers or filter discs completely enclose the core layer.

At this point, it should again be expressly pointed out that the term "sandwich-like" presupposes at least three layers, of which at least one layer is enclosed by two further layers in between. Two-layer composite materials are therefore not "sandwich-like". Furthermore, the terms layer, layer and pane are to be understood as a 3-dimensional (sponge) structure which, due to the ratio of the surface to the thickness, have these designations for the sake of simplicity.

In another embodiment, the core layer of aramid fabric can also be directly coated with one of the materials from the group of cellulose or plastic or polymer, in particular polypropylene and / or PTFE (dip coating, spraying and similar direct coatings), preferably vapor-deposited. With this structure, not only is the surface of the core layer completely enclosed / covered, but also the surface of the fluid exchange openings in the core layer is coated (i.e. the filter material not only covers the two flat sides of the aramid fabric layer facing away from each other but penetrates into their pores). This means that the entire surface of the aramid fabric, i.e. the core layer, is completely coated with one of the above-mentioned materials. As a result, the direct coating not only protects the aramid fabric from UV radiation and chemical influences from acids or the like, but also prevents the shorter fibers of the aramid fabric from becoming detached from the fabric and reaching the sterile area. Another advantage of direct coating through the filter material is that the size or diameter of the fluid exchange openings can be controlled directly through the coating duration. Such a coating independently forms fluid exchange openings in the coating, which adapt to the fluid exchange openings in the aramid fabric.

Such a multi-layer (preferably at least three-layer) filter / sterile packaging ensures mechanical resilience, which manifests itself in the fact that the filter / sterile packaging is essentially puncture-proof and is not punctured or damaged badly by a sharp or pointed surgical instrument can. On the other hand, the multi-layer (preferably at least three-layer) structure also prevents aramid fibers from being released from the aramid fabric and entering the sterile room. At the same time, the filter / sterile packaging, which is made up of several layers, remains elastic and insensitive to pressure and bending loads. With a multi-layer filter / sterile packaging as described above, longer maintenance intervals can also be realized, which means that replacement is only rarely required, which in turn leads to a reduction in costs. Another advantage of the aforementioned filter materials from the cellulose or plastics group, especially polypropylene, or PTFE is that these materials protect the aramid fabric from UV radiation. In the case of aramid fabrics, UV radiation initially causes a visible discoloration from the original light yellow to a bronze-brown shade. After prolonged exposure to UV radiation, the fiber loses up to 75% of its strength.

In other embodiments, the filter / sterile packaging can also have more than three layers in cross section, for example several aramid layers or several layers made of the known filter materials, preferably plastic, which are arranged between the aramid layers and / or also envelop the at least one aramid layer. In yet another embodiment, the multilayer filter / sterile packaging can also be formed from only two layers or filter disks. In an embodiment with two filter disks, the aramid layer is on the side facing away from the items to be sterilized and the other filter layer is on the side facing the items to be sterilized.

Aromatic polyamide (aramid) is also known under the name Kevlar®. Aramid fibers have a high specific (weight-related) strength, low density, high impact strength, good heat resistance and dimensional stability, good vibration damping and a high work capacity. Aramid fibers show good resistance to solvents, fuels, lubricants, salt water, etc.; However, some strong acids and alkalis attack aramid fibers. They are resistant to attack by fungi and bacteria. Aramid fibers are widely used. They are best known for their use in safety clothing (splinter vests, cut protection gloves). The fibers have a high mechanical strength.

Since the individual aramid fibers are short, they can under certain circumstances become detached from the aramid fabric. In order to prevent these fibers from getting into the medical sterilization container or the sterilized area of a sterile packaging, the aramid fabric is encased in a further filter material made of one of the already known materials, so to speak, the filter is multilayered, ie in this case a sandwich structure. In the preferred embodiment, the filter / sterile packaging is constructed in three layers, with the middle layer consists of the aramid fabric, which is enclosed on both sides by filter material from the above-mentioned known group, preferably made of PTFE. The aramid fabric in the multilayer filter / sterile packaging with an aramid core is thus flexible, possibly elastic and / or insensitive to pressure and bending loads.

The filter / sterile packaging, more precisely, the preferably at least two outer layers or filter disks, can in one embodiment have a larger surface diameter than the core layer and be glued to one another at their outer edges of the disks, or the outer layers can also be glued directly to the core layer be. Such a structure is easy to implement, which lowers manufacturing costs. Due to this structure, the core layer is preferably completely enclosed by the two outer layers.

The core layer and the outer layers of the filter / sterile packaging have fluid exchange openings / pores, as has already been stated above. In one embodiment, the fluid exchange openings of the core layer can preferably have larger diameters than the fluid exchange openings of the outer layer. This has the advantage that you can use a coarser and therefore cheaper puncture-proof aramid fabric in the core, and a finer material, i.e. a material with smaller fluid exchange openings, as the outer layer.

The fluid exchange openings of the at least one outer layer can, in one embodiment, be smaller than the diameter of fibers of the aramid fabric. Since the fibers cannot migrate through the outer layer, it is ensured that the fibers do not get into the sterilized space and contaminate it.

The multi-layer filter can be essentially circular, square or rectangular. It can also have any other shape in order to be adapted to a filter holding device in a medical sterilization container. In addition, other shapes can also be implemented, such as bags or pouches made of this multilayered filter composite material for surgical To pack cutlery or material. The filter is preferably a permanent filter, but it can also be designed as a disposable filter.

Furthermore, a method for producing a multi-layer filter for a medical sterilization container (s) or a multi-layer sterile packaging is presented. The method includes enclosing a core layer made of aramid fabric with at least one other (filter) material, the at least one other material from the group cellulose or plastic, preferably made of polypropylene (eg Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon ®, DuPont), or consists of another (filter) material with similar / comparable mechanical / chemical properties.

The method of manufacturing the filter can further include gluing two separate filter disks or outer filter layers together. The filter disks / filter layers are preferably made of a material from the cellulose or plastic group, preferably made of polypropylene (e.g. Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon®, DuPont). The filter discs / filter layers (including the aramid fabric) are glued to their outer edge. The outer edge here is to be understood as the (frame) surface that lies on the side facing the other filter disk / filter layer and is located in the vicinity of the outer circumference of the filter disk / filter layer, whereby proximity to the outer circumference is preferably a distance to the outer circumference of the respective filter disk / filter layer is to be understood, which is less than ninety percent of the radius / cross-sectional dimension, preferably less than 50 percent and particularly preferably less than 10 percent of the radius / cross-sectional dimension.

Another manufacturing process involves enclosing the core layer made of aramid fabric by (direct) coating, preferably by vapor deposition, of the core layer, particularly preferably with a material from the group cellulose or plastic, preferably made of polypropylene (e.g. Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec ® / DuPont) or PTFE (e.g. Teflon ®, DuPont), whereby in particular through the Steam the (filter) material is applied directly to the aramid fabric. Each surface of the intermediate layer (aramid fabric) is completely coated with the (filter) material.

In a preferred embodiment, a medical sterile packaging has a multi-layer filter consisting of a core layer or core layer made of an aramid fabric as a puncture protection. The core layer or core layer is completely enclosed by at least one first outer layer or outer layer made of a filter material on one side thereof and / or by at least one second outer layer / or outer layer made of a filter material on the other side (beyond the peripheral edge of the core layer).

The present invention is explained in more detail below on the basis of preferred embodiments with reference to the accompanying figures.

Figure description

• Fig. 1 shows a medical sterilization container.
• Fig. 2 shows a filter holder for a medical sterilization container.
• Fig. 3 Fig. 10 shows the manufacturing process of a first embodiment of a multilayer filter.
• Fig. 4 shows the structure of the first embodiment of a multilayer filter in cross-sectional view.
• Fig. 5 shows the structure of a second embodiment of a multilayer filter in cross-sectional view.
• Fig. 6 Fig. 13 shows the manufacturing process of a third embodiment of a multilayer filter.
• Fig. 7 shows the structure of a third embodiment of a multilayer filter in cross-sectional view.

Detailed description

In Fig. 1 a multi-layer filter 1 is shown in a holding device 2 of a medical sterilization container 3. In this case, the filter 1 is designed as an approximately circular disc and is enclosed, preferably clamped, in the frame-like holding device 2, which in turn is fastened to the medical sterilization container 3.

In Fig. 2 the structure of the filter holding device 2 for a multilayer filter 1 in a medical sterilization container 3 is shown. The filter holding device 3 consists of a lattice-like retaining ring 4 and a grating or perforated plate-like retaining plate 5, which hold / clamp the multi-layer filter 1 between them. As a result, passage openings are created in the filter holding device 3, both in the holding ring 4 and in the holding plate 5, which enable fluid to be exchanged between the interior of the sterilization container 3 and its surroundings and at the same time protect the multi-layer filter 1 from coarse / large-area forces.

In Fig. 3 shows the manufacturing method and the structural design of a multilayer filter 1 according to a first embodiment of the present invention. Accordingly, all the elements of the multilayer filter 1 (composite material / composite membrane) are stacked on top of one another, so that they are all arranged centrally along an imaginary axis (in the direction of the membrane thickness). The term “elements” is to be understood as meaning the individual layers or filter disks of the multi-layer filter 1.

The multi-layer filter 1 has a lowermost / outermost first layer / layer 6 made of a filter material preferably from the group cellulose or plastic, preferably made of polypropylene (eg Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon ®, DuPont). The at least one middle, second layer / layer, namely the core layer 7, consists of an aramid fabric. The top / outermost third layer 8 is again made of a material from the cellulose or plastic group, preferably made of polypropylene (eg Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (eg Teflon®, DuPont). This preferred sandwich-like structure is exemplary and can also relate to several further layers / plies made of aramid and also several layers / plies made of the filter materials already mentioned or materials with similar (filter) properties. All layers / plies have fluid exchange openings (pores) 9, the first and third layers / ply 6, 8 having fluid exchange opening diameters (pore size) which are smaller than the fiber diameter of the aramid fabric of the second layer 7.

In the manufacturing process for the first embodiment of the multilayer filter 1, the individual layers / plies are glued by means of an adhesive or by means of ultrasonic welding in the vicinity of the outer circumference of the two outer layers / plies 6, 8 and thus close the second layer 7, namely the aramid fabric (loosely) a.

The two outer layers / layers made of suitable filter material thus form the actual filter membrane with corresponding filter properties, whereas the middle layer / layer made of aramid fabric (exclusively) represents a puncture protection. Accordingly, if the filter 1 is damaged on a flat side by the action of mechanical force and the filter properties of one outer layer / layer are thus canceled / impaired, the other outer layer / layer remains undamaged through the intermediate layer of aramid fabric and its filtering effect is thus intact.

In Fig. 4 the cross section of the first embodiment of the multilayer filter 1 according to the first embodiment is shown. In this embodiment, all fluid exchange openings / pores 9 of the layers have the same fluid exchange opening diameter / pore diameter. The intermediate layer made of aramid fabric, i.e. the second layer 7, is between the other two, outer ones Layers 6 and 8 embedded and completely enclosed. The peripheral edge-side contact / connection areas 10 of the two outer layers / plies are glued to one another, but can also be interwoven, caulked, riveted or the like for production reasons. In this embodiment, only the two outer layers / layers are firmly connected to one another and the middle layer / layer is loosely received between them. The two outer layers / plies can also be firmly connected (glued) to one another on the middle filter. Other exemplary embodiments of gluing are also obvious, which include a complete enclosure of the core layer, for example welding (preferably ultrasonic welding) or pressing.

In Fig. 5 A second embodiment of a multi-layer filter 1 is shown in which the two outer layers / plies have a fluid exchange opening diameter or pore diameter that is smaller than the fluid opening exchange diameter of the core layer 7. The method for its production corresponds to the first preferred embodiment.

In Fig. 6 the manufacturing method of a third embodiment of a multilayer filter 1 is shown. The aramid core, i.e. the middle layer with a coating material 11 from the cellulose or plastic group, is preferably made of a polymer, in particular polypropylene (e.g. Kimguard ™ / Kimberly-Clark), polyethylene (Tyvec® / DuPont) or PTFE (e.g. Teflon®, DuPont) ) coated. This can be done through plastic and powder coating, wet painting, spray-sintering processes, electrothermal processes and vapor deposition.

In Fig. 7 the cross section of a third embodiment of the multilayer filter 1 is shown as a whole and in a detailed view. In this embodiment, all outer sides (top and bottom) of the aramid fabric 7 and also all fluid exchange openings / pores 9 formed by the aramid fabric 7 (pore inside) are coated with a (filter) material 11 of the already known group. Here, the coating not only reaches the layer surfaces or disk surfaces of the aramid fabric 7 but also the inner surfaces of the fluid exchange openings / pores 9. The multi-layer filter 1 according to the third In this embodiment, the preferred embodiment of the present invention is not formed from three individual separate layers but from a middle layer 7, namely the aramid fabric, and a coating 11 that completely envelops it and penetrates its pores.

In summary, the invention relates to a multilayer filter of a (medical) sterile container or a (medical) sterile packaging, each consisting of a core layer made of an aramid fabric, which is covered or completely enclosed by at least one outer layer made of at least one other material, preferably PTFE and very particularly preferably Teflon is, a method for producing the multi-layer (medical) filter of a sterile container or for producing the (medical) sterile packaging and the use of a composite membrane as a multi-layer filter of a (medical) sterile container or as (medical) sterile packaging, wherein the composite membrane consists of a core layer of a Aramid fabric, which is covered or completely enclosed by at least one outer layer made of at least one other material, preferably made of PTFE and very particularly preferably made of Teflon.

List of reference symbols

1. 1. Multi-layer filter
2. 2. Filter holder
3. 3. Medical sterilization container
4. 4. Retaining ring
5. 5. Retaining plate
6. 6. first layer
7. 7. second layer (core layer, aramid fabric)
8. 8. Third layer
9. 9. Fluid exchange ports
10. 10. Contact point
11. 11. Coating

Claims (12)

1. A multilayer filter (1) of a medical sterilization container (3) or a medical sterile packaging, each consisting of a core layer or core sheet (7) made of an aramid fabric as puncture protection, which is fully enclosed by at least one first outer layer or outer sheet (6) made of filter material on one side thereof and by at least one second outer layer or outer sheet (8) made of filter material on the other side thereof.
2. The filter (1) or sterile packaging according to any of the preceding claims, characterized in that all layers/sheets (6, 7, 8) of the filter (1) have fluid exchange openings or pores (9) which allow the exchange of fluids, in particular gases, between the environment and the interior of the medical sterilization container (3) or sterile packaging.
3. The filter (1) or sterile packaging according to any of the preceding claims, characterized in that the at least one first outer layer/sheet or the at least one first and second outer layers/sheets (6, 8) consists/consist of a material of the group consisting of cellulose or plastic, preferably polypropylene, polyethylene or PTFE.
4. The filter (1) or sterile packaging according to any of the preceding claims, characterized in that the at least one first and second outer layers (6, 8) have a larger surface diameter than the core layer (7) and are bonded together at their outer edge surrounding the core layer (7), or in that the at least one first and second outer layers (6, 8) are directly bonded to the core layer (7).
5. The filter or sterile packaging according to any of claims 2 to 4, characterized in that the fluid exchange openings or pores (9) of the at least one first outer layer (6) or of the at least one first and second outer layers (6, 8) are smaller than the diameter of fibers of the aramid fabric (7).
6. The filter (1) or sterile packaging according to any of claims 1 to 3, characterized in that the core layer (7) is coated with a coating material (11) from the group consisting of cellulose, polymer, polypropylene and/or PTFE, and is preferably vaporized.
7. The filter (1) or sterile packaging according to any of the preceding claims, characterized in that the core layer (7) and the at least one outer layer (6) or the at least one first and second outer layers (6, 8) has/have fluid exchange openings or pores (9), the fluid exchange openings or pores (9) of the core layer (7) preferably having larger diameters than the fluid exchange openings or pores (7) of the at least one outer layer (6, 8).
8. A method for producing a multilayer filter of a medical sterilization container or for producing a medical sterile packaging, characterized by the following method steps:

   providing a core layer or core sheet made of aramid fabric as puncture protection,

   covering the core layer or core sheet on one side thereof as the inside with at least one first outer layer or outer sheet made of filter material and

   covering the core layer or core sheet on the other side thereof as the outside with at least one second outer layer or outer sheet made of filter material, so that the core layer or core sheet is fully enclosed.
9. The method according to claim 8, characterized in that, in the event that both sides of the core layer or core sheet are covered, the first and second outer layers are formed from two separate filter discs or membranes, preferably from a material of the group consisting of cellulose or plastic, preferably polypropylene, polyethylene or PTFE, which are directly bonded together at their respective outer edge enclosing the core layer or core sheet.
10. The method according to claim 8, characterized in that, in the event that both sides of the core layer or core sheet are covered, the core layer made of aramid fabric is coated, preferably vaporized, with the material of the first and second outer layers, the first and second outer layers preferably consisting of a material of the group consisting of cellulose or plastic, preferably polypropylene, polyethylene or PTFE.
11. Usage of a multilayer filter according to claim 1 in a medical sterilization container (3) or in a medical sterile packaging.
12. A medical sterile packaging comprising a multilayer filter (1) according to claim 1.

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